scholarly journals The Mechanisms of Size Constancy

2015 ◽  
Vol 28 (3-4) ◽  
pp. 253-283 ◽  
Author(s):  
Irene Sperandio ◽  
Irene Sperandio ◽  
Philippe A. Chouinard
Keyword(s):  
Visual Experience ◽  
Distance Perception ◽  
Brain Area ◽  
Size Perception ◽  
Retinal Images ◽  
Size Constancy ◽  
Constant Size ◽  
Sensory Modalities ◽  
The Brain

Size constancy is the result of cognitive scaling operations that enable us to perceive an object as having the same size when presented at different viewing distances. In this article, we review the literature on size and distance perception to form an overarching synthesis of how the brain might combine retinal images and distance cues of retinal and extra-retinal origin to produce a perceptual visual experience of a world where objects have a constant size. A convergence of evidence from visual psychophysics, neurophysiology, neuropsychology, electrophysiology and neuroimaging highlight the primary visual cortex (V1) as an important node in mediating size–distance scaling. It is now evident that this brain area is involved in the integration of multiple signals for the purposes of size perception and does much more than fulfil the role of an entry position in a series of hierarchical cortical events. We also discuss how information from other sensory modalities can also contribute to size–distance scaling and shape our perceptual visual experience.

scholarly journals Importance of the Paraventricular Nucleus of the Hypothalamus as a Component of a Neural Pathway between the Brain and the Testes that Modulates Testosterone Secretion Independently of the Pituitary

Endocrinology ◽  
2003 ◽  
Vol 144 (2) ◽  
pp. 594-598 ◽  
Author(s):  
Daniel J. Selvage ◽  
Catherine Rivier
Keyword(s):  
Paraventricular Nucleus ◽  
Leydig Cell ◽  
Pseudorabies Virus ◽  
Cell Function ◽  
Brain Area ◽  
Male Rats ◽  
Neural Pathway ◽  
Electrolytic Lesions ◽  
The Brain

We previously reported that in adult male rats, the intracerebroventricular (icv) injection of corticotropin-releasing factor (CRF) or the β-adrenergic agonist isoproterenol (ISO) significantly inhibited the ability of human chorionic gonadotropin (hCG) to stimulate testosterone (T) secretion. The finding that this phenomenon also took place when LH release had been blocked with an LHRH antagonist suggested that icv CRF and ISO did not alter Leydig cell function by influencing the activity of pituitary gonadotrophs. We therefore proposed the existence of a neural pathway connecting the brain to the testes, whose activation by icv CRF or ISO interfered with T secretion. Based on the intratesticular injection of the transganglionic tracer pseudorabies virus, we recently identified the paraventricular nucleus (PVN) of the hypothalamus as a component of this neural link. The aim of the present work was to investigate the functional role of this brain area in mediating the ability of CRF and ISO to inhibit the ability of hCG to stimulate T secretion. We first demonstrated that local microinfusion of CRF or ISO directly into the PVN mimicked the effect of their icv injection, suggesting that the PVN does indeed represent a site of action of ISO and CRF in altering Leydig cell responsiveness to gonadotropin. In contrast, neither CRF nor ISO microinfusion into the central amygdala or the frontal cortex influenced hCG-stimulated T secretion. To further investigate the role of the PVN in ISO- and CRF-induced blunting of hCG stimulation of T, we determined the effect of icv CRF or ISO on testicular activity of rats with electrolytic lesions of the PVN. These lesions, which did not in themselves influence Leydig cell responsiveness to hCG, blocked the effect of both icv ISO and CRF on hCG-induced T release. Collectively, these results support the hypothesis that CRF- and ISO-induced activation of cells in the area of the PVN decreases the ability of gonadotropin to release T and suggests that this nucleus represents an important site of the proposed neural connection between the brain and the testes.

scholarly journals Midkine Is a Novel Regulator of Amphetamine-Induced Striatal Gliosis and Cognitive Impairment: Evidence for a Stimulus-Dependent Regulation of Neuroinflammation by Midkine

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Marta Vicente-Rodríguez ◽  
Rosalía Fernández-Calle ◽  
Esther Gramage ◽  
Carmen Pérez-García ◽  
María P. Ramos ◽  
...  
Keyword(s):  
Brain Area ◽  
Memory Task ◽  
Long Term Effects ◽  
Y Maze ◽  
Amphetamine Treatment ◽  
Microglial Response ◽  
First Time ◽  
The Brain

Midkine (MK) is a cytokine that modulates amphetamine-induced striatal astrogliosis, suggesting a possible role of MK in neuroinflammation induced by amphetamine. To test this hypothesis, we studied astrogliosis and microglial response induced by amphetamine (10 mg/kg i.p. four times, every 2 h) in different brain areas of MK−/− mice and wild type (WT) mice. We found that amphetamine-induced microgliosis and astrocytosis are enhanced in the striatum of MK−/− mice in a region-specific manner. Surprisingly, LPS-induced astrogliosis in the striatum was blocked in MK−/− mice. Since striatal neuroinflammation induced by amphetamine-type stimulants correlates with the cognitive deficits induced by these drugs, we also tested the long-term effects of periadolescent amphetamine treatment (3 mg/kg i.p. daily for 10 days) in a memory task in MK−/− and WT mice. Significant deficits in the Y-maze test were only observed in amphetamine-pretreated MK−/− mice. The data demonstrate for the first time that MK is a novel modulator of neuroinflammation depending on the inflammatory stimulus and the brain area considered. The data indicate that MK limits amphetamine-induced striatal neuroinflammation. In addition, our data demonstrate that periadolescent amphetamine treatment in mice results in transient disruption of learning and memory processes in absence of endogenous MK.

Psychiatry and the Frontal Lobes

1990 ◽  
Vol 24 (1) ◽  
pp. 113-132 ◽  
Author(s):  
Janice D. Russell ◽  
Milton G. Roxanas
Keyword(s):  
Frontal Lobe ◽  
Psychiatric Symptoms ◽  
Brain Area ◽  
Neuropsychological Testing ◽  
Frontal Lobes ◽  
Biological Data ◽  
Frontal Lobe Damage ◽  
Psychiatric Conditions ◽  
The Brain

The frontal lobes of the brain have long been regarded as enigmatic in their function and perhaps should be considered even more so in states of dysfunction. Observed associations between structural lesions and psychiatric symptoms and the demonstration of disturbed function and morphology in the frontal lobes of individuals suffering from major psychiatric disorders have led to increased interest in this brain area. Psychiatrists have been particularly concerned with seeking the aetiogenesis of common diagnostic entities and this article attempts to synthesize the available facts. A brief overview of relevant biological data precedes a description of methods of neuropsychological testing and the clinical features arising from frontal lobe damage. A discussion of the role of the frontal lobes in some aspects of personality function follows. Neuropsychiatric features associated with known frontal lobe pathology are described, prefacing a discussion of those psychiatric conditions where an aetiological role for frontal lobe dysfunction has been proposed.

scholarly journals Body Representation in Anorexia Nervosa

2021 ◽  
Author(s):  
Anouk Keizer ◽  
Manja Engel
Keyword(s):  
Anorexia Nervosa ◽  
Body Size ◽  
Body Representation ◽  
The Body ◽  
Size Perception ◽  
Tactile Stimuli ◽  
Body Experiences ◽  
Sensory Modalities ◽  
Multisensory Information ◽  
The Brain

Anorexia nervosa (AN) is an eating disorder that mainly affects young women. One of the most striking symptoms of this disorder is the distorted experience of body size and shape. Patients are by definition underweight, but experience and perceive their body as bigger than it in reality is. This body representation disturbance has fascinated scientists for many decades, leading to a rich and diverse body of literature on this topic. Research shows that AN patients do not only think that their body is bigger than reality, and visually perceive it as such, but that other sensory modalities also play an important role in oversized body experiences. Patients for example have an altered (enlarged) size perception of tactile stimuli, and move their body as if it is larger than it actually is. Moreover, patients with AN appear to process and integrate multisensory information differently than healthy individuals, especially in relation to body size. This leads to the conclusion that the representation of the size of the body in the brain is enlarged. This conclusion has important implications for the treatment of body representation disturbances in AN. Traditionally treatment of AN is very cognitive in nature, it is possible however that changed cognitions with respect to body size experiences do not lead to actual changes in metric representations of body size stored in the brain. Recently a few studies have been published in which a multisensory approach in treatment of body representation disturbance in AN has been found to be effective in treating this symptom of AN.

scholarly journals The role of previous visual experience in subjective reactions to new affective pictures and sounds.

2021 ◽  
Author(s):  
Fiorella Del Popolo Cristaldi ◽  
Filippo Gambarota ◽  
Suzanne Oosterwijk
Keyword(s):  
Predictive Models ◽  
Visual Experience ◽  
Test Phase ◽  
Previous Experience ◽  
Group Differences ◽  
Significant Group ◽  
Affective Stimuli ◽  
Sensory Modalities ◽  
Valence And Arousal

According to predictive models of emotion, people use their previous experience to construct new affective predictions. We do not live in a stable world, however. Some environments are uncertain, others are not. This study investigated how experiencing certain vs. uncertain probabilistic relationships shapes subjective reactions to new affective stimuli, within and across sensory modalities. Two S1-S2 paradigms were employed as learning and test phases in two experiments. S1s were colored circles, S2s negative or neutral affective pictures or sounds. Participants (N = 192, 179) were assigned to the certain (CG) or uncertain group (UG), and they were presented with 100% (CG) or 50% (UG) S1-S2 congruency between visual stimuli during the learning phase. During the test phase both groups were presented with a new S1-S2 paradigm with a 75% S1-S2 congruency, and visual (Experiment 1) or auditory (Experiment 2) S2s. Participants were asked to rate the expected valence of upcoming S2s (expectancy ratings), or their experienced valence and arousal (valence and arousal ratings). In both experiments, participants in the CG reported more negative expectancy ratings after the S1s previously paired with negative stimuli, whereas no group differences emerged on valence and arousal ratings. Furthermore, when comparing the two experiments, no significant group by experiment interaction was found. Overall, and in line with predictive models, our results suggest that relying on a certain previous experience shapes subjective expectancies toward a coherent labeling of the predicted valence of future stimuli, and that this process develops similarly across sensory modalities.

scholarly journals β-Naphtoflavone and Ethanol Induce Cytochrome P450 and Protect towards MPP+ Toxicity in Human Neuroblastoma SH-SY5Y Cells

2018 ◽  
Vol 19 (11) ◽  
pp. 3369 ◽  
Author(s):  
Jesus Fernandez-Abascal ◽  
Mariantonia Ripullone ◽  
Aurora Valeri ◽  
Cosima Leone ◽  
Massimo Valoti
Keyword(s):  
Cytochrome P450 ◽  
Brain Metabolism ◽  
Brain Area ◽  
Human Neuroblastoma ◽  
In Vitro System ◽  
Protein Levels ◽  
The Brain ◽  
Cyp Isozymes

Cytochrome P450 (CYP) isozymes vary their expression depending on the brain area, the cell type, and the presence of drugs. Some isoforms are involved in detoxification and/or toxic activation of xenobiotics in central nervous system. However, their role in brain metabolism and neurodegeneration is still a subject of debate. We have studied the inducibility of CYP isozymes in human neuroblastoma SH-SY5Y cells, treated with β-naphtoflavone (β-NF) or ethanol (EtOH) as inducers, by qRT-PCR, Western blot (WB), and metabolic activity assays. Immunohistochemistry was used to localize the isoforms in mitochondria and/or endoplasmic reticulum (ER). Tetrazolium (MTT) assay was performed to study the role of CYPs during methylphenyl pyridine (MPP+) exposure. EtOH increased mRNA and protein levels of CYP2D6 by 73% and 60% respectively. Both β-NF and EtOH increased CYP2E1 mRNA (4- and 1.4-fold, respectively) and protein levels (64% both). The 7-ethoxycoumarin O-deethylation and dextromethorphan O-demethylation was greater in treatment samples than in controls. Furthermore, both treatments increased by 22% and 18%, respectively, the cell viability in MPP+-treated cells. Finally, CYP2D6 localized at mitochondria and ER. These data indicate that CYP is inducible in SH-SY5Y cells and underline this in vitro system for studying the role of CYPs in neurodegeneration.

Keeping an Eye on the Brain: The Role of Visual Experience in Monkeys and Children

1993 ◽  
Vol 120 (1) ◽  
pp. 7-19 ◽  
Author(s):  
M. L. J. Crawford ◽  
R. S. Harwerth ◽  
E. L. Smith ◽  
G. K. Von Noorden
Keyword(s):  
Visual Experience ◽  
The Brain

scholarly journals Running Changes the Brain: the Long and the Short of It

Physiology ◽  
2017 ◽  
Vol 32 (6) ◽  
pp. 410-424 ◽  
Author(s):  
Carmen Vivar ◽  
Henriette van Praag
Keyword(s):  
Brain Area ◽  
Adult Brain ◽  
Dynamic Changes ◽  
Initial Development ◽  
Neuron Number ◽  
Neurotransmitter Systems ◽  
Afferent Connections ◽  
The Brain

Exercise is a simple intervention that profoundly benefits cognition. In rodents, running increases neurogenesis in the hippocampus, a brain area important for memory. We describe the dynamic changes in new neuron number and afferent connections throughout their maturation. We highlight the effects of exercise on the neurotransmitter systems involved, with a focus on the role of glutamate and acetylcholine in the initial development of new neurons in the adult brain.

Game Theory and the brain

2011 ◽  
Vol 30 (06) ◽  
pp. 411-418
Author(s):  
M. van 't Wout
Keyword(s):  
Brain Area ◽  
Neural Responses ◽  
Neural Basis ◽  
Causal Inferences ◽  
The Social ◽  
Virtual Lesion ◽  
Lesion Studies ◽  
The Brain ◽  
Insight Into

SummaryWhat is the neural basis of why you trust one person, but not the other? How do emotions in response to unfairness guide our interactions? What are the neural responses associated with cooperation? The field of social neuroeconomics aims to answer these and other questions to better understand the neural circuitry of decision-making in social interactions. In addition to neuroimaging studies, which can give insight into a possible correlation between brain activation and a cognitive process, (virtual) lesion studies allow drawing causal inferences about the role of a particular brain area in the social decisionmaking process. This paper will review some of the more recent findings on the neural basis of fairness, trust and cooperation identified using neuroimaging or lesion studies.

scholarly journals Relative Size Perception at a Distance is Best at Eye Level

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 89-89
Author(s):  
M Bertamini ◽  
T L Yang ◽  
D R Proffitt
Keyword(s):  
Visual Field ◽  
Distance Perception ◽  
Relative Size ◽  
Size Perception ◽  
Horizon Line ◽  
The Relationship ◽  
Source Of Information

We studied the role of the horizon line as a source of information about the relative size of objects at a distance. Relative-size judgements (2AFC) were collected for two objects at 30.5 m and 23.8 m away from the observer to assess how performance depends on the relationship between the size of the objects and the eye level of the observer. In three experiments in an indoor hallway and in one experiment outdoors, accuracy was higher for objects in the neighbourhood of eye level. We consider these results in the light of two hypotheses: one which proposes that observers localise the horizon as a reference for judging relative size, ie on the basis of the horizon ratio, and another which proposes that observers perceive the general neighbourhood of the horizon and then employ a height-in-visual-field heuristic. The finding that relative-size judgements are best around the horizon implies the use of information independent of distance perception in perceiving size.

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